The IP Communications High-Density Digital Voice/Fax Network Modules are an integral part of the Cisco Unified Communications offering, delivering a versatile combination of digital voice, analog voice, and data capabilities in a single network module form factor. They not only provide the IP telephony gateway to Cisco UC architectures for calls to and from the PSTN and the WAN, but also allow enterprises to deploy networks with existing traditional telephony equipment until they are ready to migrate to IP telephony. Features include high-density digital voice and WAN connectivity up to four T1/E1 ports, analog voice connectivity up to four ports, and up to 50 conferencing and transcoding sessions1. Enterprises can now deploy all these rich features on a single network module, enabling connectivity to the PSTN, traditional telephony equipment such as PBXs, key systems, analog telephones, fax machines, and the enterprise WAN.

This product supports three network module versions, with the option of zero, one, or two built-in T1/E1 ports, as shown in Table 2. Each built-in port can be conveniently software-configured to support either T1 or E1 operation. Each network module also supports a single VIC/VWIC slot that can be fitted with a Cisco voice/WAN interface card (VWIC) or voice interface card (VIC). The Cisco VICs are daughter cards that install into the network modules and provide the interface to the PSTN and to telephony equipment (PBXs, key systems, fax machines, phones). The Cisco VWICs are daughter cards that provide the interface to the PBX, PSTN, and/or WAN. Figure 1 shows a NM-HDV2-2T1/E1 with two built-in T1/E1 ports and a VIC3-2FXS/DID in the VIC/VWIC slot.

The IP Communications High-Density Digital Voice/Fax Network Modules are used with the PVDM2 Packet Fax/Voice DSP modules, providing scalability from 4 to 120 channels and featuring the latest digital signal processing technology. A maximum of four PVDM2s can be installed on each NM-HDV2 network module. The IP Communications High-Density Digital Voice/Fax Network Modules that are deployed on the Cisco 2811, 2821, 2851, 2911, 2921, 2951, 3825, 3845, 3925 and 3945 Unified Communications Routers can also be conveniently used with the onboard PVDM2 DSP modules (on the 2800 and 3800 Series only). The PVDM2s are not supported on the Cisco 2900 and 3900 Series motherboards. Enterprises can conveniently select the minimum number and density-type PVDM2s depending on the voice channels they are deploying, and scale the number of PVDMs as they expand. These PVDM2 can be configured for high-, medium- or flex complexity via software. Flex complexity is the default configuration, and in this mode, the network module will dynamically negotiate the appropriate codec (medium or high) on a call-by-call basis depending on the PVDM2s available.

Enhanced Cisco conferencing and transcoding features on the IP Communications High-Density Digital Voice/Fax Network Modules are available. The network modules provide a hardware-based conference resource at branch offices to facilitate multiparty conferences, thereby reducing the costs of delivering conferencing resources across the WAN. Transcoding resources within the same network module further reduces bandwidth consumption and costs by compressing traffic across the WAN, and enabling communications between devices that support different codecs. Up to 50 eight-party G.711 ad-hoc conferences, and up to 32 eight-party multicodec (G.711/G.729) ad-hoc conferences can be supported on a single IP Communications High-Density Digital Voice/Fax Network Module.

Rich set of features are delivered on a single network module form factor

Features such as data WAN connectivity, high-density digital voice connectivity, analog voice connectivity and conferencing/transcoding are supported on a single network module form factor, allowing customers to utilize other network module slots for other applications. A single NM-slot platform can be deployed for small offices, providing a cost-effective solution for IP telephony.

Analog and digital voice connectivity are supported in a single network module, enabling customers to efficiently provide flexible and reliable connectivity to public or private switched telephone networks, and phones, faxes, PBXs, and key systems.

Integrated data WAN and digital voice connectivity

Voice and WAN data is integrated on the same T1 interface, providing a cost-effective way of delivering PSTN and data WAN access for small branch offices.

Supports higher-densities of digital voice connectivity

Supports up to a maximum of four T1/E1 ports in a single network module slot for digital voice connectivity, ideal for offices deploying toll bypass (transporting voice and fax traffic across the WAN to reduce or eliminate toll charges).

Features the latest digital signal processing technology that can support higher call densities per DSP, and more flexibility in channel allocation per DSP. Up to four PVDM2 slots are supported per network module, providing scalability of 4-120 channels per network module. These DSPs can be shared among multiple IP Communications High-Density Digital Voice/Fax Network Modules that are installed in an Integrated Services Router. DSPs on the motherboard on the Cisco 2811, 2821, 2851, 2911, 2921, 2951, 3825, 3845, 3925, and 3945 Integrated Services Routers can also be used with the NM-HDV2 network modules.

Built-in and easily-configurable T1/E1 ports

The convenient built-in ports can be easily configured for either T1 or E1 operation, providing flexibility when ordering, provisioning and in multi-national enterprise deployments.

There are various applications for the IP Communications High-Density Digital Voice/Fax Network Module. In the application below, CiscoUCMat headquarters delivers the call control for IP phones at the branch offices (Figure 2). Each branch office is enhanced with SRST to maintain basic telephony services at the branch office if the WAN goes down or connectivity to the Cisco UCM is lost. The IP Communications High-Density Digital Voice/Fax Network Module is integrated into the Cisco Full Service Branch Office routers located at the branch office. There is frequent voice communication between branch offices, and the PSTN. As a result, voice calls between offices are VoIP and are routed over the WAN for telephony cost savings. The NM-HDV2-2T1/E1 is used to deliver T1 WAN access for both voice and data connectivity. Calls to external parties are placed through T1 PSTN access. In addition, the VIC/VWIC slot on the NM-HDV2-2T1/E1 is populated with a VIC3-4FXS/DID to connect to analog phones and fax machines.

Figure 2. IP Telephony Application using NM-HDV-2T1/E1 (with a VIC3-4FXS/DID), and SRST in a Full-Service Branch

Supports a VIC/VWIC slot that can fitted with either digital or analog/BRI voice/WAN interface cards. Supports a maximum of 60 channels of digital voice, or four channels of analog voice in medium complexity codec. Up to four PVDM2 Packet Fax/Voice DSP modules can be used.

Includes a built-in T1/E1 port and a VIC/VWIC slot that can be fitted with either digital or analog/BRI voice/WAN interface cards. Supports a maximum of 90 channels of digital voice, or 30 channels of digital voice and four channels of analog voice in medium complexity codec. Up to four PVDM2 Packet Fax/Voice DSP modules can be used.

Includes two built-in T1/E1 ports and a VIC/VWIC slot that can be fitted with either digital or analog/BRI voice/WAN interface cards. Supports a maximum of 120 channels of digital voice, or 60 channels of digital voice and four channels of analog voice in medium complexity codec. Up to four PVDM2 Packet Fax/Voice DSP modules can be used.

DID port is used to provide off-premises DID connection from central office. Serves only incoming calls from the PSTN. Does not support caller ID in DID mode.

VIC3-2FXS-E/DID

2-port Enhanced FXS/DID voice/fax interface card.

FXS port is used to connect directly to phones, fax machines, and key systems. Generates battery polarity reversal and caller ID. VIC3-2FXS-E/DID is designated as an "Off-Premise Extension Lite" product offering. This means that while the module addresses a subset of the off-premise extension applications, it should be noted that the module is not in full compliance for off-premise usage.

DID port is used to provide off-premises DID connection from central office. Serves only incoming calls from the PSTN. Does not support caller ID in DID mode.

FXO port is used to connect to PBX or key system, or to provide off-premise connections to PSTN. Supports battery reversal detection and caller ID. These VICs can be software configured to work in all countries. Also used to connect to analog CAMA trunk to provide dedicated E-911 service (North America only).

FXO port is used to connect to PBX or key system, or to provide off-premise connections to PSTN or PTT. Supports battery reversal detection and caller ID. These VICs can be software configured to work in all countries. Also used to connect to analog CAMA trunk to provide dedicated E-911 service (North America only).

Use to connect as network side or user side to PBX or key system as off-premise connections (ISDN voice BRI). Supports Patent Pending flexible L2 and L3 configurations

VWIC2-1MFT-T1/E1

1-Port T1/E1 Multiflex Trunk Voice/WAN Interface Card

Used to connect to PBX, PSTN, or WAN using T1/E1 standard interface and provide channel drop-and-insert capability.

VWIC2-2MFT-T1/E1

2-Port T1/E1 Multiflex Trunk Voice/WAN Interface Card

Used to connect to PBX, PSTN, or WAN using T1/E1 standard interface and provide channel drop-and-insert capability.

VWIC2-1MFT-G703

1-Port G.703 Multiflex Trunk Voice/WAN Interface Card

Used to support unstructured E1 (G.703) and all features of the other Cisco MFT VWIC2 modules, including drop-and-insert.

VWIC2-2MFT-G703

2-Port G.703 Multiflex Trunk Voice/WAN Interface Card

Used to support unstructured E1 (G.703) and all features of the other Cisco MFT VWIC2 modules, including drop-and-insert. Additional flexibility is provided on the two port module with the capability to configure one port for unstructured E1 (G.703) while configuring the other for standard framed E1.

PVDM2s on a NM-HDV2 module or on the mother board of an ISR router can be shared across multiple IP Communications High-Density Digital Voice/Fax Network Modules. Please see Table 4 below for a list of PVDM2 modules supported.

PVDM3s equipped on the motherboards of the 2911, 2931, 2951, 3925, 3945 Unified Communications routers can coexist with the PVDM2s on the NM-HDV2 modules as long as they are not both installed in the same domain. The motherboard PVDM slots form one domain and each SM slot forms a separate domain. The motherboard domain can contain either all PVDM2 modules or all PVDM3 modules. An SM domain can only contain PVDM2 modules housed by the NMHDV2 carrier card. If a mix of PVDM2s and PVDM3s are detected on the motherboard slots, then the PVDM2s will be deactivated, allowing only the PVDM3s to be used actively. If PVDM2s are detected in service-module slots and PVDM3s are installed on the motherboard, then both will continue to function in their own domain and coexist.

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Call admission control and PSTN fallback: Uses Service Assurance Agent (SAA) to determine latency, delay and jitter and provide real-time ICPIF calculations before establishing a call across an IP infrastructure. SAA packets emulate voice packets receiving the same priority as voice throughout the entire network.

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Silence suppression, voice activity detection (VAD): Bandwidth is used only when someone is speaking. During silent periods of a phone call, bandwidth is available for data traffic.

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Comfortnoise generation: This feature reassures the phone user that the connection is being maintained, even when no voice packets are being transmitted.

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Private line automatic ring-down (PLAR): Provides a direct connection to another digital or analog voice port by lifting a telephone handset on one end. Includes "Trader Turret" PLAR.

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Local/Advanced Voice Busy-Out (LVBO/AVBO): Automatically busies out any desired voice trunk line to a PBX or PSTN when a direct WAN or LAN connection to the router or any part of the network to the destination port is down.

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ISDN BRI network side and phantom power: The VIC2-2BRI-NT/TE provides the ability to connect a PBX/PABX configured as user side directly to the router. Also provides phantom power to accommodate equipment that requires it.

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Analog CAMA trunk connection: The VIC2-2FXO and VIC2-4FXO provide the ability to connect to analog CAMA trunks which provide dedicated E-911 services. Each VIC port can be individually configured as an FXO or a CAMA port via Cisco IOS Software.

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Per port disable: Allows disabling of any single port without affecting any other port on the same VIC or NM.

• LED indicators for voice processing resources and port status.

Fax and Modem

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Fax and modem passthrough: Allows fax and modem traffic to pass through a voice port.

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Fax relay: Provides a more robust protocol for fax transmission over packet networks. Also supports the T.37 and T.38 fax protocols.

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Dual clocking domain: Supports a second clocking domain for one T1/E1 data only trunk, independent of the primary clocking domain used by other T1/E1 and BRI ports resident within a single NM-HDV2 module.

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Flexi-DSP architecture: There is no need to specify codec complexity at configuration. An appropriate codec is dynamically selected when a call is established, while allocating DSP resources optimally.

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Feature upgrades: The DSP architecture allows for addition of new features through simple code updates.

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DSP sharing: Supports the ability to share DSPs among multiple NM-HDV2 modules within a single Voice Gateway Router.

1Conferencing/transcoding feature available on the 2800 Series starting with 12.3(8)T4, 3800 Series starting with 12.3(11)T, 2900 and 3900 Series starting with 15.0(1)M.

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